Switzerland has frozen all assets belonging to Hosni Mubarak and his family, which could run into hundreds of millions, the government announced.

The move came as the former president was reported to have flown to the Red Sea resort of Sharm el-Sheikh, where he has previously chaired summits, received guests and enjoyed the winter sunshine well away from the crowds.

Mubarak said in his first speech during the uprising on 1 February that he would not leave his homeland, pledging to "die on the soil of Egypt and be judged by history".

But exploratory discussions involving the Saudis, the US and the UAE have reportedly taken place about him moving to Dubai. One important issue is immunity from any prosecution he might face on charges of crimes against humanity after 300 deaths and documented abuses by the security forces.

According to the London-based paper al-Quds al-Arabi, revelations about the Mubarak family fortune and possible legal action over that are also a factor in planning for a post-presidential future.

Experts have estimated that the Mubaraks could be worth £43.5bn, with much of the wealth from investment deals in British and Swiss banks or tied up in upmarket real estate in London, New York, Los Angeles and expensive tracts of the Red Sea coast.

In Britain, sources say the Bank of England cannot act against Mubarak's UK assets, which are thought to be considerable, unless it receives a formal request from either the EU, UN or a new Egyptian government. No requests have, as yet, been forthcoming.

Mubarak's half-Welsh wife, Suzanne and their sons, Gamal and Alaa, were able to accumulate wealth through partnerships with foreign investors and companies, dating back to when he was in the army and in a position to benefit from corporate corruption.

It had been thought that Mubarak might be persuaded to again seek urgent medical treatment in Germany, where he spent three weeks convalescing after surgery last March. But Omar Suleiman, the vice-president, denied on Wednesday that this option was under consideration. Germany has also denied offering him hospitality.

A peaceful retirement in Sharm el-Sheikh would be an unusual outcome for an Arab president in the post-second world war era. Several Lebanese presidents retired after serving their terms in office, but otherwise Arab leaders have mostly either died in office or been murdered.

In Tunisia, human rights campaigners are attempting to unravel the former president Zine al-Abidine Ben Ali's web of assets, believed to spread from Canada and South America to the Gulf, and draw a "blacklist" of misappropriated assets.

A Tunis prosecutor opened an investigation into the overseas assets of the ousted leader and his family. Much of the fortune, allegedly made from pillaging the economy, is believed to be held in property and secret bank accounts.

A number of countries, including France, are examining requests to identify and block any movement of funds belonging to members of the Ben Ali regime, including relatives of his second wife, Leila Trabelsi. She was reported to have fled last week to Saudi Arabia with 1.5 tonnes of gold worth €50m (£42m).